ENS Event | |
|---|---|
10:00 Aug 17, 2010 | |
| Title | Unanalyzed Condition Due to Potential Wiring Discrepancy |
| Event Description | On August 16, 2010, at about 0100 PDT, SONGS Unit 2 Train 'A' Emergency Diesel Generator (EDG) 2G002 was removed from service for planned maintenance. Train 'A' EDG is the Appendix R protected Train.
At about 1545 the same day, Southern California Edison (SCE) discovered a potential wiring discrepancy in the electronic governor. At 0300 on August 17, 2010, SCE determined two wires on a fire isolation fuse were confirmed to be terminated differently than specified in plant drawings and that the discrepancy would prevent the fuse and associated fire isolation switch from performing its Appendix R fire isolation function for the Train 'A' EDG. In accordance with NUREG-1022, Rev. 2, SCE is reporting this occurrence in accordance 10CFR50.72(b)(3)(ii)(B). While the incorrect wiring impacted the Appendix R qualifications of the Train 'A' EDG, it did not impact its other design functions and the EDG was capable to fulfill its safety function for all other Design Basis Events. Therefore, SCE considers the safety significance of the condition to be minimal. In accordance with LCS specification 3.7.113.1 Condition A, SCE will implement hourly Fire Watches for the impacted plant areas until such time that the wiring on the Unit 3 Train 'A' Emergency Diesel Generator 3G002 is conformed to be correct or has taken actions to correct any wiring discrepancy. An evaluation will be conducted to determine the cause of this condition. At the time of this occurrence, Unit 2 and Unit 3 were both at 100% power." The NRC Resident Inspector will be notified of this occurrence and will be provided with a copy of this report.
The licensee is retracting the event based on the following: Upon further investigation, SCE determined the suspected wiring discrepancy was only an issue with an elementary diagram that was used for circuit verification. SCE had already flagged this elementary diagram as requiring revision and a change to the diagram was pending and had not been released to the field. The fire isolation fuse was wired correctly." Consequently, SCE is retracting the 8-Hour Telephone Notification made to the NRC on August 17, 2010 (Event Log No. 46182)." The NRC Resident Inspector will be notified of and will be provided with a copy of this retraction. Notified the R4DO (Clark) |
| Where | |
|---|---|
San Onofre  California (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+3.93 h0.164 days <br />0.0234 weeks <br />0.00538 months <br />) | |
| Opened: | Leon Rafner 13:56 Aug 17, 2010 |
| NRC Officer: | Joe O'Hara |
| Last Updated: | Sep 14, 2010 |
| 46182 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 515542015-11-19T21:00:00019 November 2015 21:00:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Spent Fuel Pool Temperature Outside Limits ENS 461822010-08-17T10:00:00017 August 2010 10:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Potential Wiring Discrepancy 2015-11-19T21:00:00 | |